Contamination of materials intended for human contact, consumption or ingestion, including medicine, foodstuffs or beverages, by relatively volatile materials arising from packaging materials has been a common problem for many years. The introduction of off odors and off flavors into foods and beverages has become an increasing problem with the introduction of printed packaging. The contamination can arise from coatings, volatile ink components, fountain solution formulations, recycled materials, additives and other sources in the packaging. These undesirable contaminants produce an organoleptic stimuli, particularly to those consumers quite sensitive to the presence of unexpected or undesirable odors and flavors, that can result in waste and negative reactions from the consumer. The problem has been particularly worsened because of the increasing need for colorful, eye-catching, market oriented printing on consumer packaging in snack food, breakfast cereal, TV dinner, carbonated beverage and other strongly consumer oriented products.
The contamination problem can arise in printed materials with colorful legends on virgin or recycled cardboard, paper or label stock using typical lithographic technology. Printed materials are complex structures having multiple layers and a variety of materials that can be added to or coated onto individual layers. The combination can arise from chemicals used in manufacturing the individual layers, coating materials onto the layers, from printing inks used in manufacturing the printed materials, fountain solutions, additives, coatings and any other component in the manufacturing process. Such contamination typically arises from volatile organic compounds that arise from the printed structure and released into the atmosphere internal or external to the packaging material.
Such volatile materials that seem particularly objectionable include compounds with a reactive carbonyl group: wherein R is independently aromatic, aliphatic, alykl or other group and X is R or H or OH. Representative materials include aldehyde, ketone, carboxylic acids or other volatile C1-24 organic compounds containing a carbonyl group. Many of these compounds have a strong off odor or off flavor that can contaminate the odor or flavor of foods or beverages. Such materials can have a detection threshold of as little as one part of volatile compound per billion parts of either food or atmosphere. Further, proximate to printing installations, the airborne concentration of these volatile organic materials can create an undesirable or harmful environment for printing workers.
Numerous attempts have been made to improve methods for removing or trapping carbonyl compounds. Gaylord, U.S. Pat. No. 4,374,814; Bolick et al., U.S. Pat. No. 4,442,552; Scott et al., U.S. Pat. No. 4,480,139; and Scott et al., U.S. Pat. No. 4,523,038, all discuss the use of organic compounds having pendant hydroxyl groups as aldehyde scavengers. An aldehyde is one species of carbonyl compound having the structure R—CHO; wherein the R group is typically aromatic or aliphatic group and the CHO represents a carbonyl with a bonded hydrogen. Other volatile compounds can have a aldehyde group a ketone or carboxylic group. These patents all appear to teach these polyhydric water soluble organic compounds that can, through an aldol condensation, react with an aldehyde to trap gaseous aldehyde.
A different scavenging technique, using polyalkylene amine materials to scavenge unwanted aldehydes from polyolefin polymeric materials, is taught by Brodie, III et al., U.S. Pat. Nos. 5,284,892, 5,362,784 and 5,413,827; and Honeycutt, U.S. Pat. Nos. 5,317,071 and 5,352,368. In unrelated technology, Gesser, U.S. Pat. No. 4,892,719, utilizes a coating of a polymeric hydrazine or polymeric amine (polyethylenimine, polyallylamine, polyvinylamine) with a plasticizer on a fiberglass or paper air filter to trap sulfur oxides, H2S, CH2O and other acidic gases. Langen et al., U.S. Pat. No. 4,414,309, use heterocyclic amine compounds as aldehyde scavengers in photoemulsions used in photographic materials. Nashef et al., U.S. Pat. No. 4,786,287 and Trescony et al., U.S. Pat. No. 5,919,472, utilize an amine compound in implantable bioprosthetic tissues to reduce residual aldehyde concentrations.
In a non-analogous technology. Cavagna et al., U.S. Pat. No. 5,153,061, claims the use of absorbing coatings such as activated carbon to reduce the migration of chlorinated dioxins or chlorinated furans from paperboard materials. Meyer, U.S. Pat. No. 4,264,760, uses a sulfur compound at a valence of +5 to −2 inclusive in the form of a sulfuroxyacid as a aldehyde scavenger to reduce aldehyde odor. Aoyama et al., U.S. Pat. No. 5,424,204, claim stabilization of glucose 6-phosphate dehydrogenase with hydroxylamine aldehyde scavengers and other compounds. Wheeler et al., U.S. Pat. No. 5,545,336, teach methods of neutralizing aldehyde in waste waters through an aldehyde sodium pyrosulfite reaction. Flexographic printing inks and related fountain solutions are taught in Cappuccio et al., U.S. Pat. No. 5,567,747, and Chase, U.S. Pat. No. 5,279,648, respectively. Lastly, Osamu, JP 10-245794, teaches a wet strength agent for cellulosic webs constituting a free formaldehyde scavenger (comprising urea, melamine, sulfite, ammonium or guanidine salt) combined with a wet strength agent such as urea formaldehyde or melamine formaldehyde resin.
In spite of substantial efforts in controlling aldehyde and other off odors and flavors in printing composition and resulting packaging materials, a substantial need exists to reduce release of contaminating off odors or off flavors. Further, a need to provide a lithographic fountain solution, a lithographic printing process, an over-coating for lithographic processes and a resulting lithographically printed product characterized by a reactive chemistry that traps or reduces release of a carbonyl compound arising from the coating, ink, fountain solution, printed legend, printed packaging material or process is extant.